Antimicrobial and antifungal polymer fibers, fabrics, and methods of manufacture thereof

ABSTRACT

High-melting antimicrobial polymer fibers and antimicrobial fabrics comprising such fibers are prepared by preparing a masterbatch of polymer pellets (e.g., PET), silver and copper salts, and a compounding agent which provides free flowing polymer pellets which can be prepared in advance, with a long shelf life. Polymer masterbatches prepared by the methods of the invention can produce limited color or off-white antimicrobial fibers and fabrics using conventional melt spinning manufacturing methods. Fabrics incorporating fibers of the present invention are potent inhibitors of Athlete&#39;s foot fungi, gram negative and gram positive bacteria, and drug resistant pathogens.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/864,957, filed Aug. 12, 2013.

FIELD OF THE INVENTION

The present invention relates, inter alia, to the composition andproduction of antifungal and antibacterial polyester materials, forexample fibers and fabric blends containing such fibers.

BACKGROUND OF THE INVENTION

Increasing attention has been paid to the dangers of microorganismcontamination from everyday exposures. While primarily a concern for awide range of healthcare facilities, and food processing and preparationfacilities, it is also a concern for schools, public transport, the homeand businesses. Healthcare facilities where microbial bio-burden is aconcern include large multi-unit hospitals, specialized clinics, veteranaffairs hospitals, long term care facilities, retirement homes andindividual or group doctors or dental offices among others.

Drug resistant strains of pathogenic bacteria are being identifiedaround the world, and the spread of these microorganisms from local toregional to worldwide is well documented. New microorganisms, or morevirulent forms of existing micro-organisms, especially antibioticresistant strains, are also being discovered, and can readily spreadworldwide due to the growing ease of travel, and the developingworldwide market for goods. Microorganisms of concern include but arenot limited to bacteria of all sorts, fungi, parasites, and many typesof viruses. Although regular cleaning and good sanitation practices canbe effective means of reducing microbial bio-burden, it would bebeneficial to provide materials which are inherently resistant to, orminimize the spread of microorganisms.

The antimicrobial properties of silver have been known for a very longtime. The pharmacological properties of silver are described in “HeavyMetals” by S. C. Harvey and in “Antiseptics and Disinfectants:Fungicides; Ectoparasiticides” by S. Harvey in The Pharmacological Basisof Therapeutics, Fifth Edition, Goodman and Gilman (editors), MacMillanPublishing Company, NY, 1975. The mechanism of action of silver has alsobeen described by Clement and Jarrett in Metabolism Based Drugs 1(5-6),467-482. Some basic mechanisms of action which have been identifiedinclude degradation of bacterial enzymes, cell wall degradation,inhibition of cell mitotic activity, degradation of cytoplasmicstructures, and interaction with DNA bases. It is recognized in theliterature that both metallic silver and silver ions are antimicrobial,but that ultimately antimicrobial activity is mediated through thedissolution of silver ions into the bacterial microenvironment.

Silver sulfate is a well-known, commercially available material that canbe synthesized by conventional aqueous precipitation methods. Thereaction of aqueous solutions of silver nitrate and sulfuric acid toform silver sulfate was described by Richards and Jones in Z. anorg.Allg. Chem 55, 72, (1907), and an improvement on the method waspublished by Hahn and Gilbert Z. anorg. Allg. Chem 258, 91, (1949).Silver salts are generally known to be thermally and photochemicallyunstable, forming brown, gray or black products. Silver sulfate may bereduced to its metallic state, with the corresponding oxidation ofchemical elements in its environment. It can also be converted to orconverted to silver oxide (black) or silver sulfide (black) by exposureto air. Silver metal generated by thermal reduction on a polymericsubstrate will exhibit a UV absorption band at 390 nm which isattributable to the surface plasmon resonance of silver.

One use of silver based antimicrobials is for textiles. Various methodsare known in the art to introduce antimicrobial properties to a targetfiber. The approach of embedding inorganic antimicrobial agents, such aszeolites, into low melting components of a conjugated fiber is describedin U.S. Pat. Nos. 4,525,410, and 5,064,599. In another approach, theantimicrobial agent can be delivered during the process of making asynthetic fiber such as those described in U.S. Pat. Nos. 5,180,402,5,880,044, and 5,888,526, or via a melt extrusion process as describedin U.S. Pat. Nos. 6,479,144 and 6,585,843. In yet another process, anantimicrobial metal ion can be ion-exchanged with an ion-exchange fiberas described in U.S. Pat. No. 5,496,860. High-pressure laminatescontaining antimicrobial inorganic metal compounds are disclosed in U.S.Pat. No. 6,248,342. Deposition of antimicrobial metals ormetal-containing compounds onto a resin film or fiber has also beendescribed in U.S. Pat. Nos. 6,274,519 and 6,436,420. An antimicrobialmixture of zinc oxide and silver sulfate on an inorganic powder supportis disclosed in JP 08133918. An antimicrobial masterbatch formulation isdisclosed in JP 2841115B2 wherein a silver salt and an organicantifungal agent are combined in a low melting wax to form a masterbatchwith improved mixing and handling safety. More specifically, silversulfate was sieved through a 100 mesh screen (particles sizes less thanabout 149 microns), combined with 2-(4-thiazolyl)benzimidazole andkneaded into polyethylene wax. This masterbatch material was thencompounded into polypropylene, which was subsequently injection moldedinto thin test blocks which exhibited antibacterial properties withrespect to E. coli and Staphylococcus, and antifungal properties withrespect to Aspergillus niger. Similar masterbatches are also describedin JP 03271208, wherein a resin discoloration-preventing agent (e.g. UVlight absorbent, UV light stabilizer, antioxidant) is also incorporated.

Silver sulfate has been used as an antimicrobial agent in multiplemedical applications. Incorporation of inorganic silver compounds inbone cement to reduce the risk of post-operative infection following theinsertion of endoprosthetic orthopaedic implants was proposed andstudied by J. A. Spadaro et al (Clinical Orthopaedics and RelatedResearch, 143, 266-270, 1979). Silver chloride, silver oxide, silversulphate and silver phosphate were incorporated inpolymethylmethacrylate bone cement at 0.5% concentration and shown tosignificantly inhibit the bacterial growth of Staphylococcus aureus,Escherichia coli and Pseudomonas aeruginosa. Antimicrobial wounddressings are disclosed in U.S. Pat. No. 4,728,323; wherein a substrateis coated with an antimicrobially effective film of a silver salt,preferably silver chloride or silver sulfate. Antimicrobial wounddressings are disclosed in W02006113052A2, wherein aqueous silversulfate solutions are dried onto a substrate under controlled conditionsto an initial color, which is color stable for preferably one week underambient light and humidity conditions. An antimicrobial fitting for acatheter is disclosed in U.S. Pat. No. 5,049,140 which describes atubular member composed of a silicone/polyurethane elastomer in which isuniformly dispersed about 1 to 15% wt. of an antimicrobial agent,preferably silver sulfate. A moldable plastic composite comprisingcellulose and a urea/formaldehyde resin is disclosed in WO2005/080488A1, wherein a silver salt, specifically silver sulfate, isincorporated to provide a surface having antiviral activity.

Despite various references to the proposed use of silver salts asantimicrobial agents in various polymers as referenced above, there islittle or no disclosure in the art of methods for preparingsilver-containing materials comprising higher melting polymers such aspolyethylene terephthalate (PET) polyester. Even the relativelythermally stable silver sulfate salt is converted to metallic silverwhen heated excessively in an organic matrix at the temperaturesnecessary to melt and extrude PET, for example in processes for makingpolyester (e.g., PET) fiber. Other silver salts such as the silverhalides and silver nitrate are even more thermally sensitive than silversulfate and are thus more prone to reduction to metallic silver ifprocessed at high temperature, for example under typical polyester fiberproduction process conditions.

In order to avoid problems with the thermal instability of silver saltsduring fiber production, various processes have been proposed in whichdifferent dispersions of silver salts in multi-component mixtures havebeen applied to fabrics of different compositions as topical agentsafter the fiber has been extruded, or after the fabric has beenconstructed. However, fabrics in which e.g. silver salts have beentopically applied exhibit poor laundering properties and leaching of thetopical silver salt from the topical fabric coating. It is alsodifficult to control the amount of silver salt topically absorbed ontothe surface of the fiber or the fabric because of the various finishingsolutions, dyes flame retardants or other agents commonly applied tofibers or textiles. Topical coatings on textile grade fibers or fabricsmay have utility in certain settings, but are viewed as a fundamentallydifferent technology relative to a textile grade polyester fiber havingthe antimicrobial agent incorporated into the fiber during the fiberextrusion process.

In addition, the use of metallic silver nanoparticles as antimicrobialand antifungal agents in textiles has been attempted but has generallybeen unsuccessful due to problems with clumping and other challenges,and it is been difficult to obtain a controlled, uniform dispersion andconcentration of the metallic silver nanoparticles in the final textileproduct. Theoretically, the high surface area of the metallic silvernanoparticles offers an advantage over micron sized metallic silverparticles as antimicrobial and/or antifungal agents due to the nature ofthe ion release mechanism. The release mechanism involves water oroxygen mediated oxidation and dissolution of silver ions from the silvermetal surface, which occurs in proportion to the surface area. However,metallic silver nanoparticles are difficult to incorporate into textilesto produce a product having desirable properties including durableantibacterial and/or antifungal biocidal activity after repeated use andwashings.

A method for incorporating metallic silver nanoparticles into polyesterand other synthetic polymeric fibers is disclosed in U.S. Pat. No.8,183,167. However, this technology suffers from the disadvantage thatmetallic silver nanoparticles release silver ions more slowly thanparticles of silver salts such as silver sulfate. In addition, it isrecognized in the literature that metallic silver nanoparticles can beabsorbed into cells directly and have their own toxicity characteristicsseparate from that of silver ions. Incorporation of metallic silvernanoparticles into the fiber during polymer extrusion, or topicallytreating fibers or fabrics with metallic silver nanoparticles afterextrusion, is considered a very different technology compared toincorporating silver salt particles into the extruded fiber.

Foss et al. in U.S. Pat. Nos. 6,723,428, 6,841,244, and 6,946,196disclosed multilayer and multicomponent antimicrobial fabrics andarticles employing preferably silver-containing zeolites asantimicrobial agents, for example in a thin “shell” layer on theexterior of the fiber, in a relatively low melting carrier polymer (e.g.PETG), or in a latex which is used as a vehicle for impregnating e.g. ashoe insole. When a low melting polymer carrier is used, the fabriccontaining the low melting polymer and incorporated antimicrobial agentis heat activated to melt the polymer and disperse the antimicrobialagent throughout the fabric.

BRIEF SUMMARY OF THE INVENTION

In one embodiment, the present invention is directed to a novelpolyester fiber comprising a high melting polymer (e.g., a polymermelting in the range of about 260° C. or higher) which has a processingtemperature of at least about 290° C. such as polyethylene teraphthalicacid polymer (PET), nylon 6,6, or other high-melting fibers describedherein, a silver salt of formula Ag_(a)X_(b)Y_(c) Z_(d) such as a silversulfonate or silver I sulfate, with a particle size of between 800nanometers and 20 micrometers, a copper salt of formulaCu_(a)X_(b)Y_(c)Z_(d), such as copper II sulfate, and a compoundingagent. A nonlimiting list of suitable compounding agents include one ormore of: polydimethylsiloxane (CAS 63148-62-9), dimethylsiloxane,hydroxyl terminated polydimethylsiloxane (CAS 70131-67-8), amorphoussilica (CAS 7631-86-9), aliphatic petroleum distillates (CAS64742-47-8), or liquefied petroleum gas (CAS68476-86-8). The novelcomposition also may include additional ingredients, such as pigments(e.g. titanium dioxide), and optical brighteners such as thecommercially available OB1 (4,4′-bis(benzoxazol-2-yl) stilbene). Invarious embodiments, the silver salt is dispersed in the fiber (e.g.polyester or PET fiber) at a concentration of about 0.05% to about 1.0%by weight. The silver salt Ag_(a)X_(b)Y_(c) Z_(d) may have an oxidizingagent such as NaIO₄ incorporated in it at a concentration of about 0.2to about 5% weight of the Ag_(a)X_(b)Y_(c) Z_(d). In various embodimentsthe copper salt is dispersed in the polyester fiber at a concentrationof about 0.01% to about 1.0% by weight. In various embodiments thecompounding agent is present in the final polyester at a concentrationof about 0.01% to about 0.1% by weight. The titanium dioxide is presentin the final polyester at a concentration of about 0.03% to about 0.6%by weight. The optical brightener (e.g., OB1) may be present in thefinal polyester at a concentration of about 0.01% to about 0.1% byweight. Thus, in some embodiments, the final polyester could bedescribed by a Formula I: Ag_(a)X_(b)Y_(c) Z_(d) (about 0.05 to about0.50%)+Cu_(a)X_(b)Y_(c)Z_(d) (about 0.01 to about 0.1%)+NaIO₄ (about0.0002 to about 0.025%)+compounding agent (about 0.01 to about0.1%)+TiO₂ (about 0.03 to about 0.6%)+OB1 (about 0.01 to about 0.1%)+PET(about 99.85% to about 98.5%).

Wherein:

-   -   PET is a polyethylene terephthalate polymer    -   OB 1 is an commercial optical brightener    -   NaIO₄ is sodium periodate    -   TiO₂ is titanium dioxide    -   Ag is silver I or silver II and a is 1 to 4    -   X_(b) is sulfur (S) and b is 1 to 4    -   Y_(c) is oxygen (O) and c is 2 to 8    -   Z_(d) is defined as an alkyl group R, or an aryl group Ar and d        is 0 or 1        Wherein

R is

-   -   hydrogen,    -   C₁-C₁₄ alkyl    -   C₃-C₈ cycloalkyl    -   C₁-C₈ alkyl optionally substituted by C₃-C₆ cycloalkyl,    -   C₁-C₈ alkyl optionally substituted by C₆-C₁₀ aryl    -   and Ar is C₆-C₁₀ aryl optimally substituted by R, halogen (F,        Cl, Br, I)

In another embodiment, the present invention is directed to methods ofmanufacturing antimicrobial fiber compositions as described herein,wherein the silver salt is exposed to a minimal heat history. Suchmethods incorporate a master batch approach, in which the master batchhas between about a 4% and about 20% loading of the silver salt offormula Ag_(a)X_(b)Y_(c) Z_(d.)

The silver salt is adhered to the surface of the high melting polymer(e.g. PET) pellet in a uniform manner such that about 10 to about 90% ofthe surface of individual pellets, using a mixture of the compoundingagents listed herein, is coated. Polymer pellets such as PET are eitherround, cubic, or cylindrical, and have either smooth surfaces orirregular surfaces. This “compounded master batch” can be described bythe following formula: [Ag_(a)X_(b)Y_(c) Z_(d)(w₁%)/Cu_(a)X_(b)Y_(c)Z_(d) (wt₂%)/Compounding Agent (wt₃%)/PET(wt₄%)],wherein the sum of the weight percents is 100%, and the weight percentof the Ag_(a)X_(b)Y_(c) Z_(d) is about 1% to about 26% and the weightpercent of the Cu_(a)X_(b)Y_(c)Z_(d) is about 0.1% to about 2.6% and theweight % of the compounding agent is about 0.15 to about 3%, and thepolymer (e.g. PET) makes up the difference. The compounded master batchis prepared by combining freshly dried polymer (e.g. PET) with thecompounding agent and mixing thoroughly such that the compounding agentevenly covers the surface of the polyester pellets, e.g., by tumblingthe pellets in the presence of the compounding agent. Once the pelletsare covered, a mixture of the appropriate amount of Ag_(a)X_(b)Y_(c)Z_(d) powder and Cu_(a)X_(b)Y_(c)Z_(d) powder are mixed together andthen added to the polymer pellets covered with the compounding agent,and mixed until a free flowing mass of coated polymer pellets isobtained. The modified polymer pellets prepared in the described manner,are subsequently mixed with master batches of titanium dioxide, OB1 andunmodified polymer at ambient temperature and humidity, prior to beingloaded into an extruder which, in the case of PET, is heated at about295° C.

In another embodiment, the process of the present invention is capableof producing fiber having an off-white color. Such off-white fibers canbe used to produce fabrics which can be described as having “limited”color, in other words, white or off-white.

The fibers and the fabrics of the present invention, as describedherein, are surprisingly able to kill microbes deposited on theirsurfaces. In specific embodiments, the fibers and fabrics of the presentinvention are surprisingly active against gram negative bacteria or grampositive bacteria. In still other embodiments, the fibers and fabrics ofthe present invention are surprisingly able to kill microbes depositedon the surface of the fiber or resulting fabric, including microbesknown to be resistant to conventional antimicrobial agents, includingcarbapenemase producing Klebsiella pneumonia, Methicillin ResistantStaphylococcus aureus, Vancomycin Resistant Enterococcus, MDRPseudomonas aeruginosa, MDR Acinetobacter, 3^(rd) GenerationCephalosporin Resistant E. cloacae, Acinetobacter baumannii, andFluconazole Resistant Candida albicans.

The fibers and the fabrics of the present invention, as describedherein, are also surprisingly active against fungal microbes ofdifferent types, in particular against fungi associated with Athlete'sfoot, for example the fungus Trichophyton mentagrophytes (T. menta)which is an important component of the fungi that make up Athlete's footinfections.

In still other embodiments, the fibers and fabrics of the presentinvention can be washed 25 to 100 times using standardized washingprocedures such as the AATCC 61 protocol, and maintain theirantibacterial and antifungal activity, for example as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features, embodiments, and advantages of the present inventionwill become apparent from the following detailed description withreference to the drawings, wherein:

FIG. 1 is a graphical illustration of a typical particle sizedistribution of silver sulfate particles used in the present invention;

FIGS. 2a-2c are graphical illustrations of DSC characteristics ofvarious samples;

FIG. 3 is a set of SEM data for fibers of Example 14, including thenormal SEM image and the backscatter SEM image;

FIG. 4 is an EDX spot spectrum for fibers of Example 14;

FIG. 5 is an SEM image (left) and a backscatter detection SEM image(right) of a polyester fiber according to the present invention withantimicrobial silver salt (silver sulfate) particles incorporated in thefibers;

FIG. 6 is an SEM backscatter image of cut polyester fibers according tothe present invention;

FIG. 7 is an EDX analysis of an SEM image of cut polyester fibersaccording to the present invention;

FIG. 8 is a graphical illustration of the antibacterial properties ofthe fiber compositions of Table 2 against E. coli;

FIG. 9 is a flow diagram of an exemplary method of converting fiber tofabric;

FIG. 10 is a graphical illustration of an effect of dry cleaning onfabric privacy curtains;

FIG. 11 is a bar graph illustrating the results set forth in Table 12concerning antimicrobial activity against T. mentagrophytes; and

FIG. 12 is a set of images comparing a control fabric (left) withoutantimicrobial silver particles and fabric 091812F1-UW (right) afterexposure to T. mentagrophytes.

DETAILED DESCRIPTION OF THE INVENTION

All patent applications, patents, patent publications, and literaturereferences (including ASTM or other analytical methods) cited in thisspecification, whether referenced as such, are hereby incorporated byreference in their entirety. In the case of inconsistencies, the presentdescription, including definitions, is intended to control.

The present invention provides for fibers, filaments, yarns, fabric,textiles and the like possessing excellent long-term antimicrobialefficacy, even after a substantial number of washings. Such propertiesare realized by the use of fibers or filaments having incorporatedtherein, by the methods of the present invention as described herein, aparticular silver salt and reagents used to incorporate the silver saltinto the fibers or filaments.

As used herein and as context allows, the terms “textile” and “textiles”are intended to include fibers, filaments, yarns and fabrics, includingknits, wovens, non-wovens, and the like. For purposes of this invention,textiles may be composed of or made from synthetic fibers orcombinations of synthetic fibers and natural fibers. In variousembodiments, textiles in the form of fibers and yarns may be of a sizeor denier ranging from about 1 denier per filament to about 3 denier perfilament, more particularly from less than about 1 denier per filamentto about 2 denier per filament. However, other fiber or yarn sizes maybe employed.

It is also contemplated that the fibers or yarns of the presentinvention may be mono-component, multi-component or bi-component fibersor yarns, including those that may be splittable, or which may have beenpartially or fully split, along their length by chemical or mechanicalaction as well as those of the core-sheath type construction. The fibersor yarns may be multi- or mono-filament, may be false-twisted ortwisted, or may incorporate multiple denier fibers or filaments into onesingle yarn through twisting, melting and the like. Fabrics may beformed of any of the foregoing fibers and yarns or combinations thereof.For example, a fabric may be wholly or partially made of multi- orbi-component fibers and yarns. Additionally, the fabrics may be made offibers and yarns of different compositional make-up, includingcombinations of natural and synthetic fibers and yarns, combinations ofnatural fibers and yarns, or combinations of synthetic fibers and yarns.Fabrics may be comprised of fibers and yarns such as staple fibers,filament fiber, spun fiber, or combinations thereof. Furthermore, thetextiles may be comprised of antimicrobial fibers and yarns incombination with fibers and yarns free of the antimicrobial agents.

As noted, textiles of the present invention may comprise only fibersaccording to the present invention, or may be composed of or made from acombination of natural or synthetic fibers with the antimicrobialsynthetic fiber(s) of the present invention. A non-limiting list ofnatural fibers includes wool, cotton, flax, hemp, bamboo fibers, andblends thereof. Synthetic fibers include fibers made of, for example,polyesters, acrylics, polyamides, polyolefins, polyaramids,polyurethanes, regenerated cellulose (i.e., rayon) and blends thereof.More specifically, polyester fibers include, but are not limited to,polyethylene terephthalate, poly(trimethylene terephthalate),poly(triphenylene terephthalate), polybutylene terephthalate, aliphaticpolyesters (such as polylactic acid (PLA), polyglutaric acid (PLG), andcombinations thereof, and are generally characterized as long chainpolymers having recurring ester groups. Polyamides include, but are notlimited to, nylon 6; nylon 6,6; nylon 12; nylon 6,10, nylon 1,1 and thelike and are characterized by long-chain polymers having recurring amidegroups as an integral part of the polymer chain. Polyolefins include,but are not limited to polypropylene, polyethylene, polybutylene,polytetrafluoroethylene, and combinations thereof. Polyaramids include,but are not limited to, poly-p-phenyleneterephthalamid (i.e., Kevlar®),poly-m-phenyleneterephthalamid (i.e., Nomex®), and combinations thereof.

Any of the synthetic polymers disclosed herein, having a high meltingpoint, e.g. above about 250° C., and as high as about 310° C. (orhigher) are particularly suitable for use in the present invention, asit is particularly difficult to process such high melting pointpolymers, containing the anti-microbial silver and copper salts of thepresent invention, without thermally degrading in particular the silversalts. In addition, synthetic polymers suitable for use in the presentinvention include polymers which require elevated processing conditions,for example processing conditions above about 290° C. In order to meltprocess (e.g., melt spin) polymers suitable for forming fibers intextiles, the processing temperature must be sufficiently high,depending upon the additives (if any) present in the composition, and/orthe molecular weight of the polymer, such that the melt viscosity issufficiently low to form good quality fibers. Accordingly, polymers suchas PET, which has a melting point of approximately 265° C., are oftenprocessed at temperatures ranging from about 290° C. to about 310° C. inorder to achieve melt viscosities sufficiently low to form good qualityfibers. Thus, polymers requiring melt processing at temperatures aboveabout 290° C., for example about 290° C., about 295° C., about 300° C.,about 305° C., about 310° C., about 315° C., or about 320° C., inclusiveof all values, ranges or subranges there between, and irrespective ofpolymer melting point, are suitable for use in the present invention.

The compositions and methods of the present invention are not limited tohigh-melting polymers, but can also be applied to other polymerstypically used to form fibers via a melt-spinning process. Because theprocess of the present invention reduces the thermal history experiencedby a polymer, particularly in the preparation of a masterbatchcontaining antimicrobial agents such as silver salts, the presentinvention is particularly efficacious for preparing antimicrobial fibersof relatively high-melting point polymers such as PET. In someembodiments, the polyester compositions and fibers of the presentinvention can also include small amounts of polymeric additives, such asliquid crystal polymers (LCP), polyamides, (co-) polymers based onacrylics. Such additives, when present in small amount can improve theproperties of the polyester (e.g. PET), for example by formingmicro-fibrils in the polyester melt, which can, for example, increasethe windup speed of the PET fibers. The compositions and methods of thepresent invention may also be suitable for use with lower meltingpolymers even those which may require lower processing temperatures, ifthe polymers and compositions are thermally sensitive at the temperaturerequired to melt spin good quality fibers.

The textile substrate may be dyed or colored with any type of colorant,such as pigments, dyes, tints and the like, to provide other aestheticfeatures for the end user. Other additives may also be present on and/orwithin the textile substrate, including antistatic agents, brighteningcompounds, nucleating agents, antioxidants, UV stabilizers, fillers,permanent press finishes, softeners, lubricants, curing accelerators,and soil release agents, which improve the wettability and washabilityof the textile. All of such additional materials are well known to thoseskilled in the art and are commercially available.

In accordance with one embodiment, the present invention is directedtowards a novel composition of high melting polymer fibers (e.g. havinga melting point of greater than about 260° C.) for example polyesterfibers comprising a conventional polyethylene terephthalic acid polymer(PET). However, the compositions and process of the present inventioncan also be used to prepare superior antimicrobial compositions of lowermelting polymers such as PLA, nylon 6, nylon 6,6, and polypropylene. Thecompositions of the present invention further comprise a silver saltAg_(a)X_(b)Y_(c) Z_(d) such as silver sulfate with a particle size ofbetween about 800 nanometers and about 20 micrometers, and in particularwith particles having a size distribution ranging from about 1 to about10 microns with a median of about 5 microns, a copper salt of formulaCu_(a)X_(b)Y_(c)Z_(d), such as copper II sulfate pentahydrate oranhydrous copper II sulfate, and in particular anhydrous copper IIsulfate, and a compounding agent comprising one or more of the followingmaterials: polydimethylsiloxane (CAS 63148-62-9), hydroxyl terminatedpolydimethylsiloxane (CAS 70131-67-8), amorphous silica (CAS 7631-86-9),aliphatic petroleum distillates (CAS 64742-47-8), or liquefied petroleumgas (CAS68476-86-8). The composition may optionally include pigmentssuch as titanium dioxide, and a commercially available opticalbrightener such as OB1 (4,4′-bis(benzoxazol-2-yl) stilbene) from DaltonClariant. Other optional components include pigments such as PhthalloBlue, Carbon Black, quinacridone violet, etc., including any pigmentsdyes, coloring agents, or brightening agents conventionally used intextile manufacturing.

The silver salt, which can be any of the silver salts Ag_(a)X_(b)Y_(c)Z_(d) discussed herein, particularly silver sulfate, is incorporatedinto the fiber, and typically dispersed in the fiber at a concentrationof up to about 1% by weight, such from about 0.05% up to about 1% byweight, or from about 0.05% to about 0.50% by weight, including about0.05, about 0.06, about 0.07, about 0.08, about 0.09, about 0.1, about0.15, about 0.2, about 0.25, about 0.3, about 0.35, about 0.4, about0.45, about 0.5, about 0.55, about 0.6, about 0.65, about 0.7, about0.75, about 0.8, about 0.85, about 0.9, about 0.95, and about 1% byweight, inclusive of all ranges and subranges therebetween. The silversalt Ag_(a)X_(b)Y_(c) Z_(d) may have an oxidizing agent such as NaIO₄incorporated in it at a concentration of about 0.2 to about 5% weight ofthe Ag_(a)X_(b)Y_(c) Z_(d), including concentrations of about 0.2, about0.25, about 0.3, about 0.35, about 0.4, about 0.45 m about 0.5, about0.55, about 0.6, about 0.65, about 0.7, about 0.75, about 0.8, about0.85, about 0.9, about 0.95, about 1.0, about 1.1, about 1.2, about 1.3,about 1.4, about 1.5, about 1.6, about 1.7, about 1.8, about 1.9, about2.0, about 2.1, about 2.2, about 2.3, about 2.4, about 2.5, about 2.6,about 2.7, about 2.8, about 2.9, about 3.0, about 3.1, about 3.2, about3.3, about 3.4, about 3.5, about 3.6, about 3.7, about 3.8, about 3.9,about 4.0, about 4.1, about 4.2, about 4.3, about 4.4, about 4.5, about4.6, about 4.7, about 4.8, about 4.9, and about 5.0% by weight, and allranges and subranges therebetween. The copper salt is dispersed in thefiber at a concentration of about 0.01% to about 1.0%, such as about0.01% to about 0.5% by weight, including about 0.01, about 0.02, about0.03, about 0.04, about 0.05, about 0.06, about 0.07, about 0.08, about0.09, about 0.1, about 0.2, about 0.25, about 0.3, about 0.35, about0.4, about 0.45, about 0.5, about 0.55, about 0.6, about 0.65, about0.7, about 0.75, about 0.8, about 0.85, about 0.9, about 0.95, or about1.0% by weight, inclusive of all ranges and subranges therebetween. Thecompounding agent is present in the final polymer composition (e.g. thefiber) at a concentration of about 0.01% to about 0.1% by weight,including about 0.01, about 0.02, about 0.03, about 0.04, about 0.05,about 0.06, about 0.07, about 0.08, about 0.09, and about 0.1% byweight, inclusive of all ranges and subranges therebetween. The amountof compounding agent, as described herein, is limited to the range ofabout 0.01 wt. % to about 0.1 wt. % so that the physical properties ofthe polymer component (e.g. PET) and the antimicrobial additives remainsunaffected. In addition, these levels of compounding agent facilitatemigration of the antimicrobial particles to the surface of the fiberswhere they can provide excellent activity against a wide range ofbacteria and fungi, rather than allowing them to be trapped in thecenter of the fibers which reduces the antimicrobial activity. Thetitanium dioxide, if added to the final polymer composition, is presentat a concentration of about 0.03% to about 0.6% by weight, includingabout 0.03, about 0.04, about 0.05, and about 0.06% by weight, inclusiveof all ranges and subranges therebetween. The optical brightener (e.g.,OB1) if added, may be present in the final polymer composition at aconcentration of about 0.01% to about 0.1% by weight, including about0.01, about 0.02, about 0.03, about 0.04, about 0.05, about 0.06, about0.07, about 0.08, about 0.09, and about 0.1% by weight, inclusive of allranges and subranges therebetween. Thus, the final polyester could bedescribed in one embodiment by a Formula I: Ag_(a)X_(b)Y_(c) Z_(d)(about 0.05 to about 0.50%)+Cu_(a)X_(b)Y_(c)Z_(d) (about 0.01 to about0.1%)+NaIO₄ (about 0.0002 to about 0.025%)+Compounding agent (about 0.01to about 0.1%)+TiO₂ (about 0.03 to about 0.6%)+OB1 (about 0.01 to about0.1%)+PET (about 99.85% to about 98.5%).

wherein

-   -   PET is a polyethylene terephthalate polymer    -   OB1 is a commercial optical brightener    -   NaIO₄ is sodium periodate    -   TiO₂ is titanium dioxide    -   Ag is silver I or silver II and a is 1 to 4    -   X_(b) is sulfur (S) and b is 1 to 4    -   Y_(c) is oxygen (O) and c is 2 to 8    -   Z_(d) is defined as an alkyl group R, or an aryl group Ar and d        is 0 or 1

Wherein

R is

-   -   hydrogen,    -   C₁-C₁₄ alkyl    -   C₃-C₈ cycloalkyl    -   C₁-C₈ alkyl optionally substituted by C₃-C₆ cycloalkyl,    -   C₁-C₈ alkyl optionally substituted by C₆-C₁₀ aryl

And Ar is C₆-C₁₀ aryl optimally substituted by R, halogen (F, Cl, Br, I)

In another embodiment, the present invention is directed to methods ofmanufacturing an antimicrobial (e.g., polyester) fiber as describedherein, wherein the silver salt is exposed to a minimal heat history.Typical melt processing conditions for preparing textile fibers includesforming a masterbatch (e.g. including antimicrobial agents, pigments,etc.) in an extruder at temperatures of up to about 300° C. Themasterbatch is then blended with additional polymer (e.g. PET) pelletsand melt processed, again at temperatures of up to about 300° C. to formfibers. Accordingly, typical fiber processing conditions would exposethe antimicrobial agent to two heating cycles—the first heating cycle inpreparing the masterbatch, and the second heating cycle during fiberspinning. In contrast, the process of the present invention avoids thefirst heat cycle (in preparing the masterbatch), and thus decreasesdegradation of the antimicrobial agent, particularly antimicrobialagents such as thermally sensitive silver salts.

The methods of the present invention incorporate a master batchapproach, in which the masterbatch has greater than about a 4% loadingof the silver salt of formula Ag_(a)X_(b)Y_(c) Z_(d), and in particulara loading of between about 4% and about 25% and more particularly aloading of about 9 to about 14% of the silver salt of formulaAg_(a)X_(b)Y_(c)Z_(d). Importantly, the particles of silver salt used inthe inventive manufacturing process should be between about 800nanometers and about 20 micrometers in size, and preferably should havea size distribution of about 1 to about 10 micrometers with a median ofabout 5 microns. Commercially available silver sulfate is ground andsieved, using techniques familiar to one skilled in the art to providesilver salt particles of this size. A typical particle size distributionof silver sulfate particles used in the present invention, and in thepreparation of the Examples described herein is shown in FIG. 1.

The compounding agent can include one or more of the materials describedherein. For example the compounding agent can comprise a mixture of apolydimethylsiloxane, a hydroxyl terminated polydimethylsiloxane, anamorphous silica. Alternatively, the compounding agent can comprise amixture of aliphatic petroleum distillates.

The silver salt particles of the defined size are adhered to the surfaceof the polymer (e.g., PET) pellets in an even manner covering about 10to about 90% of the surface of individual pellets, using a mixture ofthe compounding agents listed herein. The polymer pellets can have anyof a variety of shapes, including round, cubic, or cylindrical, and haveeither smooth surfaces or irregular surfaces. This “compounded masterbatch” can be described by the following formula: [Ag_(a)X_(b)Y_(c)Z_(d) (w₁%)/Cu_(a)X_(b)Y_(c)Z_(d) (wt₂%)/Compounding Agent(wt₃%)/PET(wt₄%)], wherein the sum of the weight percents is 100%, andthe weight percent of the Ag_(a)X_(b)Y_(c) Z_(d) is about 1% to about26% and the weight percent of the Cu_(a)X_(b)Y_(c)Z_(d) is about 0.1% toabout 26% and the weight % of the compounding agent is about 0.15 toabout 3%, and the PET makes up the difference.

The compounded master batch is prepared by combining freshly driedpolymer (e.g. PET) with the compounding agent (e.g., a mixture ofpolydimethylsiloxane, hydroxyl terminated polydimethylsiloxane, andamorphous silica) and mixing the combination thoroughly such that thecompounding agent evenly covers the surface of the polymer pellets, andforms a viscous mass of polymer pellets. In particular embodiments, thepolymer pellets are freshly dried (e.g., in a drying tower), and moreparticularly freshly dried at temperature between about 70 to about 90°C. Once the pellets are covered with compounding agent and have formed aviscous mass of pellets, a mixture of the appropriate amount ofAg_(a)X_(b)Y_(c) Z_(d) powder and Cu_(a)X_(b)Y_(c)Z_(d) powder are mixedtogether and then added to the pellets covered with the compoundingagent. Alternatively the Cu_(a)X_(b)Y_(c)Z_(d) powder is added first andthen the Ag_(a)X_(b)Y_(c) Z_(d) is added, or alternatively theAg_(a)X_(b)Y_(c) Z_(d) powder is added first and then theCu_(a)X_(b)Y_(c)Z_(d) powder is added. This combination of polymerpellets, compounding agents and Ag_(a)X_(b)Y, Z_(d) andCu_(a)X_(b)Y_(c)Z_(d) powders are mixed until a free flowing mass ofcoated polymer pellets is obtained, which is hereinafter referred to asa “compounded master batch.” The compounded master batch prepared in thedescribed manner, is subsequently mixed with freshly dried base polymer(e.g., PET if the masterbatch comprises a coated PET pellets), andoptionally a master batch of titanium dioxide and a master batch opticalbrightener such as OB1 from Dalton Clariant, or another opticalbrightener familiar to one skilled in the art of making fiber. Themixing of the compounded master batch and other master batches can becarried out at ambient temperature and humidity, to form a “letdownpolymer.” The letdown polymer is melt spun using conventional methods toprovide antimicrobial fibers according to the present invention. Theextrusion process (e.g. melt spinning) itself requires that thetemperature of the letdown polymer mixture is sufficiently high suchthat it forms a melt. For PET-based compositions according to thepresent invention, an extruder temperature of about 285° C. to about305° C., more particularly about 295° C. is used. The melting step maybe a separate step in, or it may be part of the extruding process. Whenthe mixture forms a melt at a sufficiently high temperature, it may beextruded using conventional melt spinning devices such as a spinneret.The resulting fiber may then be drawn, crimped, cut and spun into a yarnor other fabric depending on the intended end use, and using techniquesthat are familiar to one skilled in the art of fiber production.Alternatively the fiber can be extruded in a continuous filamentprocess.

In various embodiments, the order in which the various components of themasterbatch are mixed together can affect the overall process. Asdiscussed herein above, adding the compounding agent first to thepolymer pellets, and distributing the compounding agent uniformly overthe polymer pellets before adding the powdered antimicrobial agentsprovides a free flowing mass of coated polymer pellets which are easilyprocessed in conventional melt spinning equipment. Alternative processconditions, such as that disclosed in US 2009/0068286, in which thepowdered additives are mixed with the compounding agent first, to form apaste, and then mixed with the polymer pellets, causes agglomerates thatare trapped by the melt filters present in the fiber spinning process.As a result, such processes are more difficult to run, and the trappingof agglomerates can reduce the overall percentage of antimicrobialadditives ultimately present in the melt spun fibers.

Without being restricted to any particular mechanism, the presentinventors have found that amorphous silica is a particularly efficaciouscomponent of the compounding agent, as it acts as a desiccant and tendsto absorb moisture. This is particularly useful in polyester-based (e.g.PET) compositions and fibers, as it tends to reduce hydrolysis of thepolyester.

The fiber produced as described herein, having a composition ofAg_(a)X_(b)Y_(c) Z_(d) (about 0.1 to about 0.50%)+Cu_(a)X_(b)Y_(c)Z_(d)(about 0.01 to about 0.08%)+NaIO₄ (about 0.002 to about0.025%)+Compounding agent (about 0.01 to about 0.1%)+TiO₂ (about 0.03 toabout 0.6%)+OB1 (about 0.01 to about 0.05%)+PET (about 99.84% to about98.645%) can be analyzed by ICP-OES (induction coupled-optical emissionspectroscopy), ICP-MS (induction coupled mass spectroscopy) or AA(atomic absorbance) to confirm the overall levels of silver and copperin the fiber. These methods, familiar to one skilled in the art, allinvolve processing the fiber either by combustion or digestionconverting and heating the residue to form a plasma, and quantifying theelements present in the plasma. Representative ICP-OES data is reportedin the examples provided herein, and in general confirm the levels ofsilver and copper expected from calculations.

The fiber may also be investigated using standard fiber analysistechniques such as Favimat analysis which measures fiber physicalcharacteristics. Favimat analysis is familiar to those skilled in theart of textile fiber analysis, and involves measurement of multiplefiber properties on multiple fibers and statistically averaging theresults including, elongation up to the rupture point, the forcerequired to rupture the fiber, time to rupture, and linear density. Thephysical measurements are used to calculate fiber properties such astenacity and modulus. Favimat analysis data is reported in the Examplesand confirms that the fibers produced in the embodiments above haveFavimat analysis data consistent with fibers that can be used in textileproduction.

In a particular embodiment, PET fibers of the present invention,prepared as described herein, produce Favimat data substantially similarto that presented in Table 1 and in the Examples.

TABLE 1 Favimat Analysis Data Property Early Stage SD Example 1 SDExample 15 SD PET fiber SD Elongation 43.19% 35 107.39% 35 41.35% 15.4843.16% 20.6 Force 5.37 g 0.85 6.03 g 0.85 10.50 g 1.46 6.58 g 1.21 Workto rupture 2.71 g * cm 2.51 8.54 g * cm 2.51 4.86 g * cm 2.37 3.19 g *cm 1.91 Tenacity 2.60 g/den 0.50 2.79 g/den 0.50 5.21 g/den 0.77 3.25g/den 1.15 Linear Density 2.21 den 0.43 2.22 den 0.43 2.06 den 0.40 2.17den 0.53 Time to Rupture 26.2 sec 64.71 sec 25.26 sec 26.17 sec Modulus18.08 g/den 6.84 20.07 g/den 6.84 29.11 g/den 5.72 19.68 g/den 7.97

Fibers present invention, for example having the composition of FormulaI may also be analyzed by intrinsic viscosity which is an indirectmeasure of polymer molecular weight in the fiber. Additives can causesignificant polymer cleavage during the melting and extruding processeswhich would lead to a weaker fiber not appropriate for textileproduction. Intrinsic viscosity measurements, which are familiar tothose skilled in the art of textile fiber manufacture, can be used toidentify fibers comprising polymer with high molecular weight. Intrinsicviscosity measurements involve dissolving the polymeric fiber in anappropriate solvent such as (for PET) a mixture of phenol andtetrachloroethane, at a defined concentration such as 0.5 g/dL, at adefined temperature such as 30° C., and measuring the viscosity of theresulting solution generally using a capillary method. Intrinsicviscosity measurement data is reported in the Examples and in Table 2and is consistent with fiber of suitable quality for use in textilemanufacture. In particular embodiments, fibers of the present invention(e.g., of Formula I), prepared by the methods of the present invention,have intrinsic viscosity characteristics substantially similar to thatpresented in Table 2 and in the Examples.

TABLE 2 Intrinsic Viscosity Measurements on PET Fiber usingPhenol/Tetrachloroethane (60/40 w/w), 30° C., at a concentration of 0.5g/dL Example IV +/− 0.02 (dL/g)  1 091812F1 0.492  5 112712A 0.583 10022113F 0.489 11 022113D 0.500 12 022113G 0.500 13 022112H 0.493 14022113I 0.506 15 030613A 0.623 PET 022113A 0.494

Fibers of the present invention (e.g. of Formula I) may also be analyzedby differential scanning calorimetry (DSC) which is widely used forexamining the thermal transitions of polymeric materials. Melting points(T_(m)) and glass transition temperatures (T_(g)) of conventionalpolymers are available from standard compilations familiar to thoseskilled in the art, and can be used to show polymer degradation by thelowering of the melting temperature (T_(m)), since polymer molecularweight can correlate with melting temperature. The degree ofcrystallinity of a polymer can be estimated from the crystallizationtemperature (T_(c)) when compared to reference samples. DSC data on PETfibers of Formula I were obtained on a DSC Q1000 v9.9 instrument using a10° C. to 325° C. temperature range and are reported in the Examples.The DSC of a sample of drawn and heat set PET fiber with only TiO₂ andthe optical brightener as additives is compared to the DSC of a drawnand heat set PET fiber of the present invention (e.g., of Formula I) andundrawn amorphous polyester, in FIGS. 2a, 2b and 2c . From this data itcan be seen that the melting point (T_(m)) of the polymer in fibersprepared according to the present invention is not lower than that ofbase polymer with just TiO₂ and optical brightener after heat settingand drawing. In addition, it can be seen by comparison to the amorphousPET that the glass transition (T_(g)) and the crystallization (T_(c)) offibers of Formula I has been mostly eliminated by the drawing and heatsetting process, as would be expected. Fibers of Formula I, prepared bythe methods of the present invention, have DSC characteristicssubstantially similar to that presented in FIG. 2 a.

Because the fibers of the present invention experience less heatingcompared to fibers produced by conventional melt spinning processes(e.g., the masterbatch compositions provided by the inventive process donot require melt processing), the polymer component of the fibers andpolymer compositions of the present invention exhibit less degradation,for example as determined by measuring the molecular weight of thepolymer or intrinsic viscosity of the polymer both before and after themelt spinning process. Typically, after melt spinning, the molecularweight or intrinsic viscosity of the polymer component of the fibers ofthe present invention, prepared by the inventive process, differ fromthe molecular weight or intrinsic viscosity characteristics of thepolymer prior to melt spinning, by less than about 10%. For example, theintrinsic viscosity or molecular weight of the polymer component differsby less than about 1%, about 2%, about 3%, about 4%, about 5%, about 6%,about 7%, about 8%, about 9%, or about 10%, inclusive of all ranges andsubranges therebetween.

Fibers of the present invention (e.g. of Formula I) may also be analyzedby backscatter detection on a scanning electron microscope (SEM). SEMimages of the fibers of Formula I produced as described herein, show thedistribution of silver sulfate particles on or near the fiber surface.Backscatter detection allows elements with a higher atomic number toshow up brighter than particles with a lower atomic number (i.e. silver(Ag) with an atomic number of 47 will show up brighter than carbon (C)with an atomic number of 6). Multiple fiber samples were examined by SEMand backscatter SEM. SEM data for fibers of Example 14 in the Examplessection, including the normal SEM image and the backscatter SEM imageare shown in FIG. 3. Particles of silver sulfate on or just under thesurface are easily seen with backscatter detection. These datademonstrate that the process of the present invention successfullydelivers small particles of silver salts into the polymeric matrix ofthe PET fiber. In addition the observed silver sulfate particle sizesappear consistent with the size of the particles added (1-10 microns)and the distribution of the silver sulfate particles in the fiberappears consistent with amount of silver sulfate added, about 0.36 w %for fiber from Example 14. In a particular embodiment, fibers of FormulaI of the present invention, prepared by the methods of the presentinvention, produce backscatter SEM data substantially similar to thatpresented in FIG. 3.

Fibers of the present invention (e.g. of Formula I) may also be analyzedby electron dispersive x-ray analysis (EDX). EDX can quantify differentmetals such as silver and lower molecular weight elements such assulfur. It is a semi-quantitative method that can provide usefulinformation on the relative amounts of different elements. EDX does notgive direct information on the oxidation state or salt form of a metal,and is not very sensitive to elements present at 0.2 wt % or less.However, in the case of fibers of Example 14, since the PET base polymerdoes not contain sulfur, indirect evidence for the existence of silversulfate can be determined from the observed ratio of silver to sulfur.Fibers of Example 14 were laid down longitudinally for EDX analysis. Abulk or low magnification spectrum detects very little silver (Ag).However, analyzing the individual particles (spot spectrum) easilydetected the presence of silver (Ag). For fibers of Example 14, an EDXspot spectrum (an isolated silver particle) is shown in FIG. 4. Gold wasused in sample prep as a conductive coating, and is observed in both EDXspectrum, but is not included in the semi-quantitative information. Thew/w ratio of silver and sulfur for Ag₂SO₄ is calculated to be 6.7, whilethe observed silver to sulfur ratio is 6.4, supporting the presence ofthis salt form of silver in the fiber of Example 14. In a particularembodiment, fibers of Formula I of the present invention, prepared bythe methods of the present invention, produce EDX data substantiallysimilar to that presented in FIG. 4.

FIG. 5 shows another exemplary SEM image (left) and backscatterdetection SEM image (right) of a polyester fiber according to thepresent invention with antimicrobial silver salt (silver sulfate)particles incorporated in the fibers. The fibers have a diameter ofapproximately 15 microns, and the silver salt particles have a particlesize of about 1-10 microns. The silver salt loading is <1%.

As described above with respect to FIG. 3, the bright spots on the rightimage of FIG. 5 correspond to silver salt particles that are on or nearthe surface. Notably, very few of the silver salt particles are on ornear the surface.

FIG. 6 shows an SEM backscatter image of cut polyester fibers accordingto the present invention. This cross-sectional image shows the locationof silver salt particles as bright spots. This figure shows silver saltparticles in the interior of the fibers, and is further evidence thatthe silver salt particles are incorporated into the fibers, and notmerely coated on the fiber exterior.

FIG. 7 shows an EDX analysis of an SEM image of cut polyester fibersaccording to the present invention. EDX is an art-recognized method ofdetermining the identity of an element. The red line and yellow arrowwere added to the image to show the area that was analyzed by EDX. Thegreen peak, which was also added, indicates the presence of silver inthe area analyzed. Thus, EDX analysis also confirms that silver isincorporated into the interior of the fibers of the present invention.

The fiber compositions of Table 2 were tested for their antibacterialproperties against E. coli. The results of those tests are presented inFIG. 8. The results for sample 22113A, which does not include silverparticles, are included in FIG. 8 for comparison. FIG. 8 shows that allof the fibers tested, other than the control fiber, (i.e., all of thefibers according to the present invention) display antimicrobialactivity against E. coli.

Fibers, such as polyester fibers, containing the antimicrobial metalparticles as disclosed herein, can be converted into fabric by a varietyof methods, including any method known in the art. A person of skill inthe art will recognize that the particular method will vary depending onparameters known in the art, including the types of articles to beconstructed from the fabric, the intended use of the fabric or articlesconstructed from the fabric, the particular microbes of concern, andother factors known to or readily determinable by a person of ordinaryskill in the art. An exemplary method of converting fiber to fabric isillustrated in the flow diagram of FIG. 9.

The fiber can be produced, for example according to methods describedherein, at any suitable fiber production facility. One such suitableproduction facility is Palmetto Synthetics. The fiber can then beknitted into fabric samples by any acceptable knitting method, such asthose that are known to a person of ordinary skill in the textileindustry. Knitting can be performed at a suitable knitting facility,which may be the same or different as the fiber production facility. Onesuitable knitting facility is at Gaston College Textile TechnologyCenter. The fabric samples can then be tested for antimicrobialactivity.

For production into commercial articles, the fabric can be stored in asuitable warehouse before spinning the fiber into yarn. Spinning fiberinto yarn can be accomplished by any method, such as methods that areknown in the textile arts, at any suitable spinning facility. Onesuitable spinning facility is operated by Beal Manufacturing; anothersuitable spinning facility is operated by Pharr Yarns, Inc. Once spun,the yarn can be produced into fabric of appropriate shapes or sizes, forexample, by weavers using art recognized weaving methods. Alternatively,non-wovens can be produced using art-recognized methods.

Fabric can then be finished at an appropriate finishing facility.Finishing can comprise, for example, washing the fabric to removeweaving lubricants. Depending on the type of articles to be constructedfrom the fabric and the intended use of such articles, additionalfinishing steps can also be carried out. Such additional finishing stepscan include, for example, one or more of adding softener, addingpermanent press, and adding fire retardant.

After finishing, the fabric can be shipped to an appropriate fabricatorand manufactured into finished products, such as fabric articles.Exemplary fabric articles include uniforms, including medical such asnurse uniforms, physician uniforms, surgical operating attire, militaryuniforms, and laboratory coats, consumer articles, such as thosecommonly used in medical facilities, for example bed pads, bed sheets,pillow cases, drapes, blankets, window curtains, privacy curtains,hospital gowns, face masks, disposable underwear, and textile or gauzebandages or wound coverings, as well as other types of fabric articleswhere antimicrobial properties may be useful.

Some of the finished products can be tested for antimicrobial activity,for example, as a quality control measure. Finished products can then betransported to, for example, one or more of a warehouse, a wholesaler, aretailer, a customer, or an end user.

Fabric privacy curtains made with antimicrobial fibers were tested afterdry cleaning to determine whether the articles retain theirantimicrobial properties. A control (not dry cleaned) and negativecontrol (no silver particles) were also tested for comparison. Theresults are shown in FIG. 10.

As shown in FIG. 10, the dry cleaned curtains retain essentially all oftheir antimicrobial activity after dry cleaning. Importantly, thisresult is consistent with experiments showing that the silver particlesare incorporated into the fabric, rather than merely coated on thesurface. Silver particles coated on the surface of fibers could wash offduring dry-cleaning, which can significantly decrease the antimicrobialactivity of the fabric. However, silver particles that are incorporatedin the fabric's fibers are not easily washed off, therefore, theantimicrobial activity is retained after dry cleaning.

In another embodiment, the methods of the claimed invention providefibers with an off-white color. Fabrics comprising fibers of the claimedinvention have limited color and can be described as substantially whiteor off-white.

The fiber and the fabrics of the present invention are beingsurprisingly able to kill microbes deposited on the surface of the fiberor resulting fabric. The fabrics and fibers of the present invention aresurprisingly active against gram negative or gram positive bacteria.

The fiber and the fabrics of the present invention are surprisingly ableto kill microbes deposited on the surface of the fiber or resultingfabric, including those that are resistant to multiple knownantimicrobial agents. These resistant bacterial strains include, forexample KPC producing Klebsiella pneumonia, Methicillin Resistant Staphaureus, Vancomycin Resistant Enterococcus, MDR Pseudomonas aeruginosa,MDR Acinetobacter, 3^(rd) Generation Cephalosporin Resistant E. Cloacae,and Fluconazole Resistant Candida albicans.

Fabric comprising fibers according to the present invention, prepared bythe methods of the claimed invention, are surprisingly active againstfungal microbes of different types, and especially it is active againstfungi associated with athlete's for and especially it is active againstthe fungus Trichophyton Mentagrophytes (T. menta) which is an importantcomponent of the fungi that make up Athlete's foot infections.

The fabrics and fibers of the present invention can be washed 25 to 100times using standardized washing procedures such as the AATCC 61protocol, and maintain the antibacterial and antifungal activitydescribed herein.

EXAMPLES

General Procedure for Preparation of Compounded Master Batch

The compounding agent is weighed out into a metal mixing flask andcombined with a calculated amount of freshly dried polymer (e.g.polyester or PET) pellets at a temperature of 60 to 75° C. The mixtureis stirred for 5 to 30 minutes, without further heating or moistureprotection, and with a sufficiently powerful overhead stirrer or othermixer, until the compounding agent evenly coats the pellets, and thereare no clumps of compounding agent surrounded by polymer pellets. Themixture of compounding agent and polymer pellets is a viscous mass atthis point, and not free flowing. The silver salt and the copper saltare independently weighed out and combined and mixed until evenlydistributed solid mixture is obtained. This mixture is then added inportions to the mixture of polymer pellets and compounding agent withcontinuous stirring. As the silver and copper salts are added themixture becomes free flowing. Stirring is continued until all of thesalts are adsorbed on the surface of the pellets. The resulting pelletshave a thin coating of copper and silver salts covering anywhere from 10to 90% of the surface of the pellets depending on the amount ofcompounding agent and salts used. The covered pellets are passed througha metal mesh that removes any clumps of pellets larger than 5 or 6pellets. The filtered pellets are then passed over a finer mesh thatseparates any salt particles not attached to the surface of the pellets.The final pellets are stored in a sealed container protected frommoisture until ready to be used in a fiber production run.

ICP-OES (Induction Coupled Plasma Optical Emissions Spectroscopy) wasobtained at Galbraith Laboratories, Knoxville Tenn. Samples were ashed,then dissolved in acid prior to analysis.

Favimat Analysis was performed at Gaston College Textile TechnologyCenter, using Textechno Favimat analysis equipment.

Intrinsic viscosity measurements were done using American Society forTesting Material (ASTM) D4603-96 method which involves dissolving thepolymeric fiber in a mixture of Phenol and tetrachloroethane, at aconcentration of 0.5 g/dL, at 30° C., and measuring the viscosity of theresulting solution using the capillary method.

DSC data on fibers of Formula I were obtained on a DSC Q1000 v9.9instrument using a 10° C. to 325° C. temperature range.

Example 1 091812F1

Using General Method A

Hot (60 to 80° C.) polyester pellets (PET, cylindrical, 5 kilograms)were added to a 25 gal mechanical mixer along with 30 g of a 50% (w/w)master batch of TiO₂ in PET, and 25 g of a 5% master batch of Opticalbrightener (OB 1, Dalton-Clariant). These ingredients were mixedbriefly, and 5 mL of a mixture of 98% distillates (petroleum),hydrotreated heavy naphthenic (CAS 64742-52-5) and 2% distillates(petroleum), hydrotreated light petroleum distillates (CAS 64742-47-2)was added and mixing continued for 3 minutes, until the PET pellets wereevenly covered. Silver Sulfate (18 g, AgMPX, Eastman Kodak) was weighedout along with 2 g of anhydrous copper sulfate (CAS 7758-98-7), and bothwere added to the mixture and stirring was continued for an additionalfive minutes. This free flowing mixture was transferred to the hopper ofa Varemac pilot scale extruder, which had been running neat PET pelletsat 295° C., with an operating pressure of 500 PSI. The extruder wasfitted with a 1500 hole mesh spinneret. After five minutes the fibersexiting the extruder spinneret were observed as opaque, and werecollected in eight separate pools of fiber. Collection of the fiber wasstopped when the bulk of modified pellets in the hopper had entered theextruder. The eight pools of fiber were combined into one tow of fiberwith 12,000 strands, and feed into a pilot scale drawing and crimpingmachine. The draw rate was about 3.4:1 and the dip bath was set to about170° C. The product from the drawing and crimping was collected as loopsof crimped tow and air dried for 2 hours. This material was then heatset at 270° C. for 20 minutes, allowed to cool to room temperature, andthen cut into 1.5 inch lengths of staple fiber. The staple fiber with acalculated weight composition of 0.36% Ag₂SO₄, 0.04% CuSO₄ and 0.3%TiO₂, were characterized as follows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of120.54 mg of cut fiber was combusted to leave an inorganic residue,which was dissolved in acid and analyzed by ICP-OES: Total silver (Ag):2450 ppm, total copper (Cu): 130 ppm, total titanium (Ti): 1870 ppm.

Favimat Fiber Analysis (average of 21 fibers): Elongation: 107.39%;Force: 6.03 g; Tenacity: 2.79 g/den; Linear Density: 2.22 den; time torupture: 64.71 sec; Modulus 0-3%: 20.07 g/den.

DSC (Galbraith Laboratories) T_(g): 132° C.; T_(c): (not observed), MP:246° C. (onset: 234.3° C./53.1 J/g)

Intrinsic Viscosity (PolyTech Resources): Method: ASTM 4603-96, Solvent:Phenol/Tetrachloroethane (60/40 w/w), Temperature: 30° C.,Concentration: 0.5 g/dL, Result: 0.492 dL/g

Example 2 091812F1K-UW

The staple fiber from Example 1 was knitted into a 10 cm tube usingmethods standard textile methods. The knitted fabric was an off-whitecolor and weight composition of 0.36% Ag₂SO₄, 0.04% CuSO₄ and 0.3% TiO₂,was characterized as follows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of 59.2mg of cut fiber was combusted to leave an inorganic residue, which wasdissolved in acid and analyzed by ICP-OES: Total silver (Ag): 2430 ppm,total copper (Cu): 166 ppm, total titanium (Ti): 1850 ppm.

Example 3 092812A

Using General Method A

Hot (70 to 80° C.) polyester pellets (PET, cylindrical, 20 kilograms)were added to a 25 gal mechanical mixer along with 120 g of a 50% (w/w)master batch of TiO₂ in PET, and 100 g of a 5% master batch of Opticalbrightener (OB1, Dalton-Clariant). These ingredients were mixed briefly,and 20 ml of a mixture of 98% distillates (petroleum), hydrotreatedheavy naphthenic (CAS 64742-52-5) and 2% distillates (petroleum),hydrotreated light (CAS 64742-47-2) was added and mixing continued for 3minutes, until the PET pellets were evenly covered. Silver sulfate (72g, AgMPX, Eastman Kodak) was weighed out along with 8 g of anhydrouscopper sulfate (CAS 7758-98-7), and both were added to the mechanicalmixer and stirring was continued for an additional five minutes. Thisprocess was repeated twelve times. The individual twelve batches wereadded to the hopper of a Varemac Extruder, which had been running neatPET pellets at 295° C., with an operating pressure of 500 PSI. Theextruder was fitted with a 1500 hole mesh spinneret. After five minutesthe fibers coming from the extruder spinneret were observed as opaque.Collection of the fiber was stopped when all twelve batches of coatedpellets had entered the extruder. The pools of fiber were combined intoone tow of fiber, with 12,000 strands, and was fed into a drawing andcrimping machine. The draw rate was about 3.4:1 and the dip bath was setto about 170° C. The product from the drawing and crimping was collectedwas heat set at 270° C. for 20 minutes, cooled and cut into 1.5 inchpieces of fiber. The staple fiber with a weight composition of 0.36%Ag₂SO₄, 0.04% CuSO₄ and 0.3% TiO₂, was used directly to make fabric.

Example 4 092812AK-UW

The staple fiber from Example 3 was knitted into a 10 cm tube usingstandard textile procedures. The knitted fabric, with a weightcomposition of 0.36% Ag₂SO₄, 0.04% CuSO₄ and 0.3% TiO₂, wascharacterized as follows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of255.57 mg of staple fiber was combusted to leave an inorganic residue,which was dissolved in acid and analyzed by ICP-OES: Total silver (Ag):2270 ppm, total copper (Cu): 87 ppm, total titanium (Ti): 1740 ppm.

Example 5 112712A

Method B

Hot (70 to 80° C.) polyester pellets (PET, cylindrical, 25 kilograms)were added to a 25 gal mechanical mixer along with 270 mL of a mixtureof 98% distillates (petroleum), hydrotreated heavy naphthenic (CAS64742-52-5) and 2% distillates (petroleum), hydrotreated light (CAS64742-47-2). This mixture was stirred for five minutes until the PETpellets were evenly covered. Silver sulfate (1000 g, AgMPX, EastmanKodak) was weighed out along with 111 g of anhydrous copper sulfate (CAS7758-98-7), and both were added to the mechanical mixer and stirring wascontinued for an additional 20 minutes. The resulting mixture wassemi-free flowing. This process was repeated seventeen times. The coatedpellets from seventeen batches were combined in the hopper of amanufacturing scale extruder. The weighed hopper was set to feed in at a9.3% weight loss rate. A second hopper was filled with a 50% (w/w)master batch of TiO₂ in PET and was set to feed in at 0.6%. A thirdhopper was filled with a 5% master batch of Optical brightener (OB1,Dalton-Clariant), and was set to feed in at 0.3%. A fourth hopper wasfilled with cylindrical PET heated to 80° C. in a polyester drier, andset to a feed rate of 89.8. The extruder temperature was 285 to 315° C.The Novatec Dryer temperature was 260-300° C. A total of ten, 3002 holespinnerets were used. The pump speed was set to 3.0. The quench air wasset to 38-48° C., and a draw ratio of 3.6 was used. A 0.3% L814 finishwas applied to the fiber. This process produced 28 cans of 1.5 denierfiber, and a total of 11602 meters of spun tow. This material was thendrawn, crimped, using standard textile processing methods. The productfrom the drawing and crimping was heat set at 270° C. for 20 minutes,cooled and cut into 1.5 inch pieces of fiber in an 88% by weight yield.The staple fiber with a calculated weight composition of 0.36% Ag₂SO₄,0.039% CuSO₄ and 0.3% TiO₂, were characterized as follows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of 113.6mg of staple fiber was combusted to leave an inorganic residue, whichwas dissolved in acid and analyzed by ICP-OES: Total silver (Ag): 2090ppm, total copper (Cu): 124 ppm, total titanium (Ti): 1720 ppm.

Favimat Fiber Analysis (average of 24 fibers): Elongation: 38.05%;Force: 8.93 g; Tenacity: 5.12 g/den; Linear Density: 1.77 den; Time torupture: 23.16 sec; Modulus 0-3%: 29.83 g/den.

DSC (Galbraith Laboratories) T_(g): 124° C.; T_(c): (not observed), MP:241.8° C. (on set: 235.1° C./53.9 J/g)

Intrinsic Viscosity (PolyTech Resources): Method: ASTM 4603-96, Solvent:Phenol/Tetrachloroethane (60/40 w/w), Temperature: 30° C.,Concentration: 0.5 g/dL, Result: 0.583 dL/g

Example 6 112712K100 (112712A knitted fabric, 112712G-UW))

The staple fiber from Example 5 was knitted into a 10 cm tube usingstandard textile procedures. The knitted fabric with a calculated weightcomposition of 0.36% Ag₂SO₄, 0.039% CuSO₄ and 0.3% TiO₂, wascharacterized as follows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of326.39 mg of staple fiber was combusted to leave an inorganic residue,which was dissolved in acid and analyzed by ICP-OES: Total silver (Ag):2260 ppm, total copper (Cu): 122 ppm, total titanium (Ti): 1590 ppm.

Example 7 112712W100 (112712M100-UW)

The staple fiber from Example 5 was converted into 100% yarn and woveninto a 100% active polyester fabric using standard textile processingmethods. The woven fabric, with a calculated weight composition of 0.36%Ag₂SO₄, 0.039% CuSO₄ and 0.3% TiO₂, was characterized as follows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of 109.8mg of fabric was combusted to leave an inorganic residue, which wasdissolved in acid and analyzed by ICP-OES: Total silver (Ag): 2020 ppm,total copper (Cu): 113 ppm, total titanium (Ti): 1590 ppm.

Example 8 112712W75 (112712M75-UW)

The staple fiber from Example 5 was converted into 100% yarn and woveninto a 75% active polyester and 25% non-active polyester fabric usingstandard textile processing methods. The woven fabric, with a calculatedweight composition of 0.27% Ag₂SO₄, 0.029% CuSO₄ and 0.3% TiO₂, wascharacterized as follows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of 102.4mg of fabric was combusted to leave an inorganic residue, which wasdissolved in acid and analyzed by ICP-OES: Total silver (Ag): 1590 ppm,total copper (Cu): 91.3 ppm, total titanium (Ti): 1640 ppm.

Example 9 022113E #34

Using a general method for preparing a coated master batch (Method C),Hot PET polyester (60 to 80° C.), 360 g, of ⅜ inch cylindrical polyesterpellets was combined with 6.6 g of a paste made of 70-90% ofpolydimethylsiloxane (CAS 63148-62-9), 7-13% dimethylsiloxane, hydroxylterminated (CAS 70131-67-8) and 5-10% amorphous silica (CAS 7631-86-9).The pellets were stirred with the paste until all the pellets wereevenly covered. This provided a viscous mass of pellets. Silver sulfate(66 g, AgMPX, Eastman Kodak), and copper II sulfate (anhydrous, 7.3 g)were combined, and then added to the PET pellets. This mixture wasstirred for 5 to 10 minutes until the pellets became free flowing. Thepellets were passed over a sieve to remove unattached salts, and 10.5 gwere obtained. The weight of the coated master batch was 429 g. Assumingthat the collected salt was 90% silver sulfate, this loading of silversulfate on the PET pellets was 13% (w/w) and the copper sulfate was 1.5%(w/w). To produce fiber, 123 g of the coated master batch describedabove was combined with 27 g of a 50% master batch of TiO₂ in PET, and23 g of a 0.5% master batch of optical brightener (OB1, Dalton Clariant)and 4322 g of PET polyester pellets, mixed for 5 minutes, then added toa pilot scale extruder as described in Method A. This produced tow fiberthat was drawn and heat set as described in Method A. These fibers, witha calculated weight composition of 0.36% Ag₂SO₄, 0.04% CuSO₄ and 0.3%TiO₂ were characterized as follows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of106.83 mg of fiber was combusted to leave an inorganic residue, whichwas dissolved in acid and analyzed by ICP-OES: Total silver (Ag): 1910ppm, total copper (Cu): 114 ppm, total titanium (Ti): 1910 ppm.

Example 10 022113F #34

The coated master batch described in Example 9 was used to produce thefiber of Example 10 as follows. 170 g of the coated master batch wascombined with 27 g of a 50% master batch of TiO₂ in PET, and 23 g of a0.5% master batch of optical brightener (OB1, Dalton Clariant) and 4275g of PET polyester pellets, mixed for 5 minutes, then added to a pilotscale extruder as described in Method A. This produced tow fiber thatwas drawn and heat set as described in Method A. These fibers, with acalculated weight composition of 0.50% Ag₂SO₄, 0.057% CuSO₄ and 0.3%TiO₂ were characterized as follows.

Favimat Fiber Analysis (average of 25 fibers): Elongation: 30.63%;Force: 5.48; Tenacity: 3.17 g/den; Linear Density: 1.79 den; Time torupture: 18.65 sec; Modulus 0-3%: 37.53 g/den.

DSC (Galbraith Laboratories) T_(g): 92.8° C.; T_(c): (not observed), MP:240.7° C. (on set: 227.5° C./44.71 J/g)

Intrinsic Viscosity (PolyTech Resources): Method: ASTM 4603-96, Solvent:Phenol/Tetrachloroethane (60/40 w/w), Temperature: 30° C.,Concentration: 0.5 g/dL, Result: 0.489 dL/g

Example 11 022113D #22

Using a general method for preparing a coated master batch (Method C),Hot PET polyester (60 to 80° C.), 180 g, of ⅜ inch cylindrical polyesterpellets was combined with 2.0 g of a paste made of 70-90% ofpolydimethylsiloxane (CAS 63148-62-9), 7-13% dimethylsiloxane, hydroxylterminated (CAS 70131-67-8) and 5-10% amorphous silica (CAS 7631-86-9).The pellets were stirred with the paste until all the pellets wereevenly covered. This provided a viscous mass of pellets. Silver sulfate(20 g, AgMPX, Eastman Kodak) was added to the PET pellets. This mixturewas stirred for 5 to 10 minutes until the pellets became free flowing.The pellets were passed over a sieve to remove unattached salts. Theweight of the coated master batch was 200 g. The loading of silversulfate on the PET pellets was calculated to be 9.9% (w/w). To producefiber, 168 g of the coated master batch was combined with 27 g of a 50%master batch of TiO₂ in PET, and 23 g of a 0.5% master batch of opticalbrightener (OB1, Dalton Clariant) and 4277 g of PET polyester pellets,mixed for 5 minutes, then added to a pilot scale extruder as describedin Method A. This produced tow fiber that was drawn and heat set asdescribed in Method A. These fibers, with a calculated weightcomposition of 0.37% Ag₂SO₄, no CuSO₄ and 0.3% TiO₂ were characterizedas follows.

Favimat Fiber Analysis (average of 24 fibers): Elongation: 42.77%;Force: 6.41 g; Tenacity: 3.81 g/den; Linear Density: 1.83 den; Time torupture: 25.9 sec; Modulus 0-3%: 31.44 g/den.

DSC (Galbraith Laboratories) T_(g): 91.9° C.; T_(c): (not observed), MP:240.5° C. (on set: 227.1° C./45.42 J/g)

Intrinsic Viscosity (PolyTech Resources): Method: ASTM 4603-96, Solvent:Phenol/Tetrachloroethane (60/40 w/w), Temperature: 30° C.,Concentration: 0.5 g/dL, Result: 0.500 dL/g

Example 12 022113G #24

Using a general method for preparing a coated master batch (Method C),Hot PET polyester (60 to 80° C.), 365 g, of ⅜ inch cylindrical polyesterpellets was combined with 3.6 g of a paste made of 70-90% ofpolydimethylsiloxane (CAS 63148-62-9), 7-13% dimethylsiloxane, hydroxylterminated (CAS 70131-67-8) and 5-10% amorphous silica (CAS 7631-86-9).The pellets were stirred with the paste until all the pellets wereevenly covered. This provided a viscous mass of pellets. Silver sulfate(36 g, AgMPX, Eastman Kodak) and copper II sulfate (anhydrous, 4.0 g)were combined, and then added to the PET pellets. This mixture wasstirred for 5 to 10 minutes until the pellets became free flowing. Thepellets were passed over a sieve to remove unattached salts. The weightof the coated master batch was 398 g. The loading of silver sulfate onthe PET pellets was calculated to be 8.8% (w/w) and the loading ofcopper II sulfate was 0.98%. To produce fiber, 180 g of the coatedmaster batch was combined with 27 g of a 50% master batch of TiO₂ inPET, and 5883 g of PET polyester pellets, mixed for 5 minutes, thenadded to a pilot scale extruder as described in Method A. This producedtow fiber that was drawn and heat set as described in Method A. Thesefibers, with a calculated weight composition of 0.26% Ag₂SO₄, 0.029%CuSO₄ and 0.22% TiO₂ were characterized as follows.

Favimat Fiber Analysis (average of 24 fibers): Elongation: 61.17%;Force: 5.48 g; Tenacity: 2.56 g/den; Linear Density: 2.17 den; Time torupture: 36.98 sec; Modulus 0-3%: 17.55 g/den.

DSC (Galbraith Laboratories) T_(g): 122.3° C.; T_(c): (not observed),MP: 240.2° C. (on set: 224.8° C./48.97 J/g)

Intrinsic Viscosity (PolyTech Resources): Method: ASTM 4603-96, Solvent:Phenol/Tetrachloroethane (60/40 w/w), Temperature: 30° C.,Concentration: 0.5 g/dL, Result: 0.500 dL/g

Example 13 022113H #24

The coated master batch described in Example 12 was used to produce thefiber of Example 13 as follows. 180 g of the coated master batch wascombined with 23 g of a 0.5% master batch of optical brightener (OB1,Dalton Clariant) and 4295 g of PET polyester pellets, mixed for 5minutes, then added to a pilot scale extruder as described in Method A.This produced tow fiber that was drawn and heat set as described inMethod A. These fibers, with a calculated weight composition of 0.36%Ag₂SO₄, 0.04% CuSO₄ and no TiO₂ were characterized as follows.

Favimat Fiber Analysis (average of 25 fibers): Elongation: 47.79%;Force: 5.50 g; Tenacity: 2.83 g/den; Linear Density: 2.07 den; Time torupture: 28.97 sec; Modulus 0-3%: 16.52 g/den.

DSC (Galbraith Laboratories) T_(g): not observed; T_(c): (128.2), MP:240.25° C. (on set: 222.76° C./48.04 J/g)

Intrinsic Viscosity (PolyTech Resources): Method: ASTM 4603-96, Solvent:Phenol/Tetrachloroethane (60/40 w/w), Temperature: 30° C.,Concentration: 0.5 g/dL, Result: 0.493 dL/g

Example 14 022113I #29

Using a general method for preparing a coated master batch (Method C),Hot PET polyester (60 to 80° C.), 2000 g, of ⅜ inch cylindricalpolyester pellets was combined in portions with 18 g of a paste made of70-90% of polydimethylsiloxane (CAS 63148-62-9), 7-13% dimethylsiloxane,hydroxyl terminated (CAS 70131-67-8) and 5-10% amorphous silica (CAS7631-86-9). The pellets were stirred with the paste until all thepellets were evenly covered. This provided a viscous mass of pellets.Silver sulfate (224.2 g, AgFX, Eastman Kodak) was added in portions tothe PET pellets over 20 to 30 minutes. This mixture was stirred untilthe pellets became free flowing. The pellets were passed over a sieve toremove unattached salts (19.2 g). The weight of the coated master batchwas 2223 g. The loading of silver sulfate on the PET pellets wascalculated to be 9.2% (w/w). To produce fiber, 177 g of the coatedmaster batch was combined with 27 g of a 50% master batch of TiO₂ inPET, and 23 g of a 0.5% master batch of optical brightener (OB1, DaltonClariant) and 4268 g of PET polyester pellets, mixed for 5 minutes, thenadded to a pilot scale extruder as described in Method A. This producedtow fiber that was drawn and heat set as described in Method A. Thesefibers, with a calculated weight composition of 0.36% Ag₂SO₄, 0.04%CuSO₄ and 0.3% TiO₂ were characterized as follows.

Favimat Fiber Analysis (average of 25 fibers): Elongation: 43.19%;Force: 5.37 g; Tenacity: 2.60 g/den; Linear Density: 2.21 den; Time torupture: 26.20 sec; Modulus 0-3%: 18.08 g/den.

DSC (Galbraith Laboratories) T_(g): 112.3° C.; T_(c): (not observed),MP: 241.01° C. (on set: 228.8° C./48.72 J/g)

Intrinsic Viscosity (PolyTech Resources): Method: ASTM 4603-96, Solvent:Phenol/Tetrachloroethane (60/40 w/w), Temperature: 30° C.,Concentration: 0.5 g/dL, Result: 0.506 dL/g

Example 15 030613A

Hot PET polyester (60 to 80° C.), 2500 g, of ⅜ inch cylindricalpolyester pellets was combined with 390 g of a paste made of 70-90% ofpolydimethylsiloxane (CAS 63148-62-9), 7-13% dimethylsiloxane, hydroxylterminated (CAS 70131-67-8) and 5-10% amorphous silica (CAS 7631-86-9).The pellets were stirred with the paste for about ten minutes until anevenly distributed, viscous mass of pellets was obtained. This materialwas added to a 50 gal rotating mixer along with an additional 18.5 kg ofhot PET polyester (60 to 80° C., ⅜ inch cylindrical pellets) and stirredfor about 15 minutes until the PET pellets were evenly covered and therewere few large clumps of pellets. Copper II sulfate (anhydrous, 375 g)was weighed out and added to the rotating mixture in 2 to 3 portions.Silver sulfate (3,250 g, AgMPX, Eastman Kodak) was weighed out and addedto the rotating mixer in three portions. Mixing was continued for anadditional 20 minutes until a free flowing batch of coated pellets wasobtained. The pellets were passed over a sieve to remove large clumps ofpellets. This process was repeated five times, each time obtaining about25 kilograms of the compounded master batch. Unattached salts and largeclumps of pellets were recycled into the next batch. After the 5 runs,the pellets were sieved to remove unattached salt particles (22 g) andcombined in a storage drum to give 125,055 g of coated pellets. Theloading of silver sulfate on the PET pellets was calculated to be 12.9%(w/w).

This compounded master batch of coated pellets was converted intopolyester fiber as follows. The coated pellets were added to a hopper ofa manufacturing scale extruder. The weighed hopper was set to feed in ata 2.78% weight loss rate. A second hopper was filled with a 50% (w/w)master batch of TiO₂ in PET and was set to feed in at 0.6%. A thirdhopper was filled with a 5% master batch of Optical brightener (OB1,Dalton-Clariant), and was set to feed in at 0.5%. A fourth hopper wasfilled with cylindrical PET heated to 80° C. in a polyester drier, andset to a feed rate of 96.1%. The extruder temperature was 295° C. TheNovatec Dryer temperature was 260-300° C. A total of ten, 3002 holespinnerets were used. The pump speed was set to 3.0. The quench air wasset to 38-48° C., and a draw ratio of 3.6 was used. A 0.3% L814 finishwas applied to the fiber. This process produced 28 cans of 1.5 denierfiber, and a total of 11602 meters of spun tow. This material was thendrawn, crimped, using standard textile processing methods. The productfrom the drawing and crimping was heat set at 270° C. for 20 minutes,cooled and cut into 1.5 inch pieces of fiber in an 88% by weight yield.These fibers, with a calculated weight composition of 0.36% Ag₂SO₄,0.04% CuSO₄ and 0.3% TiO₂ were characterized as follows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of 108.8mg of fiber was combusted to leave an inorganic residue, which wasdissolved in acid and analyzed by ICP-OES: Total silver (Ag): 2290 ppm,total copper (Cu): 124 ppm, total titanium (Ti): 1650 ppm.

Favimat Fiber Analysis (average of 25 fibers): Elongation: 41.35%;Force: 10.5 g; Tenacity: 5.21 g/den; Linear Density: 2.06 den; Time torupture: 25.26 sec; Modulus 0-3%: 29.11 g/den.

DSC (Galbraith Laboratories) T_(g): 104.24° C.; T_(c): (142.91, 0.67J/g), MP: 243.4° C. (on set: 239.8° C./52.8 J/g)

Intrinsic Viscosity (PolyTech Resources): Method: ASTM 4603-96, Solvent:Phenol/Tetrachloroethane (60/40 w/w), Temperature: 30° C.,Concentration: 0.5 g/dL, Result: 0.623 dL/g

Example 16 030612W100 (not in hand)

The staple fiber from Example 15 was converted into 100% yarn and woveninto a 100% active polyester fabric using standard textile processingmethods. This fabric has a calculated weight composition of 0.36%Ag₂SO₄, 0.04% CuSO₄ and 0.3% TiO_(2.)

Example 17 030613W75

The staple fiber from Example 15 was converted into 100% yarn and woveninto a 75% active polyester and 25% non-active polyester fabric usingstandard textile processing methods. This fabric has a calculated weightcomposition of 0.27% Ag₂SO₄, 0.029% CuSO₄ and 0.3% TiO₂.

Example 18 030613W75 ceil blue scrub

The staple fiber from Example 5 was converted into 100% yarn and woveninto a fabric with 75% active polyester yarn and 25% tencel yarn, usingstandard textile processing methods. The blended fabric was dyed ceilblue in a multiple step process standard for dyeing fabrics made ofpolyester and tencel. This fabric, with a calculated weight compositionof 0.27% Ag₂SO₄, 0.029% CuSO₄ and 0.3% TiO₂ was characterized asfollows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of 102.4mg of fabric was combusted to leave an inorganic residue, which wascompletely dissolved in acid and analyzed by ICP-OES: Total silver (Ag):1590 ppm, total copper (Cu): 91.3 ppm, total titanium (Ti): 1640 ppm.

Example 19 112712B 50% Wool

The staple fiber from Example 5 was converted into 100% yarn and woveninto a 50% active polyester and 50% wool fabric using standard textileprocessing methods. This fabric, with a calculated weight composition of0.18% Ag₂SO₄, 0.02% CuSO₄ and 0.15% TiO₂ was characterized as follows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of 102.4mg of fabric was combusted to leave an inorganic residue, which wascompletely dissolved in acid and analyzed by ICP-OES: Total silver (Ag):1590 ppm, total copper (Cu): 91.3 ppm, total titanium (Ti): 1640 ppm.

Example 20 112712B 50% Cotton

The staple fiber from Example 5 was converted into 100% yarn and woveninto a 50% active polyester and 50% cotton fabric using standard textileprocessing methods. This fabric, with a calculated weight composition of0.18% Ag₂SO₄, 0.02% CuSO₄ and 0.15% TiO₂ was characterized as follows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of 102.4mg of fabric was combusted to leave an inorganic residue, which wascompletely dissolved in acid and analyzed by ICP-OES: Total silver (Ag):1590 ppm, total copper (Cu): 91.3 ppm, total titanium (Ti): 1640 ppm.

Example 21 112712K10 10% PT

The staple fiber from Example 5 was converted into a yarn of 10% activefiber and 90% Thermolite fiber, and knitted into a fabric using standardtextile processing methods. This fabric, with a calculated weightcomposition of 0.036% Ag₂SO₄, 0.004% CuSO₄ and 0.03% TiO₂ wascharacterized as follows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of 102.4mg of fabric was combusted to leave an inorganic residue, which wascompletely dissolved in acid and analyzed by ICP-OES: Total silver (Ag):1590 ppm, total copper (Cu): 91.3 ppm, total titanium (Ti): 1640 ppm.

Example 22 PURSDC116-9010

The staple fiber from Example 5 was converted into 100% active yarn, andwoven into a fabric of 10% active yarn and 90% Trevica yarn usingstandard textile processing methods. This fabric, with a calculatedweight composition of 0.036% Ag₂SO₄, 0.004% CuSO₄ and 0.03% TiO₂ wascharacterized as follows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of 102.4mg of fabric was combusted to leave an inorganic residue, which wascompletely dissolved in acid and analyzed by ICP-OES: Total silver (Ag):1590 ppm, total copper (Cu): 91.3 ppm, total titanium (Ti): 1640 ppm.

Example 23 PURSDC116-8020

The staple fiber from Example 5 was converted into 100% active yarn, andwoven into a fabric of 20% active yarn and 80% Trevica yarn usingstandard textile processing methods. This fabric, with a calculatedweight composition of 0.072% Ag₂SO₄, 0.008% CuSO₄ and 0.06% TiO₂ wascharacterized as follows.

ICP-OES (Galbraith Laboratories, GLI Procedure ME-70): A sample of 102.4mg of fabric was combusted to leave an inorganic residue, which wascompletely dissolved in acid and analyzed by ICP-OES: Total silver (Ag):1590 ppm, total copper (Cu): 91.3 ppm, total titanium (Ti): 1640 ppm.

Table 3 Summarizes the calculate composition of the different types ofmaterials in Examples 1-23. A visual assessment of the color of thedifferent fibers and fabrics is also included. The denier of the fibersin Examples 1, 5, and 10-15 is also reported.

TABLE 3 Examples 1-20 Example Description Ag₂SO₄ CuSO₄ TiO₂ Denier Color1 PET Fiber 0.36% 0.04% 0.30% 2.22 den tan 2 Knit PET Fabric 0.36% 0.04%0.30% tan 3 PET Fiber 0.35% 0.04% 0.30% tan 4 Knit PET Fabric 0.35%0.04% 0.30% tan 5 PET Fiber 0.36% 0.039%  0.30% 1.77 den tan 6 Knit PETFabric 0.36% 0.039%  0.30% tan 7 Woven PET Fabric 0.36% 0.039%  0.30%tan 100% active yarn 8 Woven PET Fabric 0.27% 0.029%   0.30%* Off white75% active yarn 9 PET Fiber 0.36% 0.04% 0.30% Off white 10 PET Fiber0.50% 0.057%  0.30% 1.79 den Off white 11 PET Fiber 0.37%   0% 0.30%1.83 den tan 12 PET Fiber 0.26% 0.029%  0.22% 2.17 den Off white 13 PETFiber 0.36% 0.04%   0% 2.07 den tan 14 PET Fiber 0.36% 0.04% 0.30% 2.21den Off white 15 PET Fiber 0.36% 0.04% 0.30% 2.06 den Off white 16 WovenPET Fabric 0.36% 0.04% 0.30% Off white 100% active yarn 17 Woven PETFabric 0.27% 0.029%  0.30% white 75% active yarn 25% polyester 18 WovenPET Fabric 0.27% 0.029%  0.30% ceil blue 75% active yarn 25% tencel 19Woven PET Fabric 0.18% 0.02% 0.15% white 50% active PET, 50% wool 20Woven PET Fabric 0.18% 0.02% 0.15% white 50% active PET, 50% cotton 21Knitted Fabric 0.036%  0.004%  0.03% white Yarn 10% active and 90%Thermolite 22 Woven Fabric 0.036%  0.004%  0.03% blue 10% active yarn90% Trevica yarn 23 Woven Fabric 0.072%  0.008%  0.06% blue 20% activeyarn 80% Trevica yarnBiological Data:

The knitted and woven fabrics were tested against gram negative(Klebsiella pneumoniae) or gram positive (Staphylococcus aureus)bacteria using the AATCC 100 protocol for testing of antimicrobialfabrics as follows. In a sterile petri dish, circles of fabric measuring4.8 cm in diameter were inoculated with 1 mL of a solution of 1×10⁵ to2×10⁶ CFU (colony forming units) of gram negative or gram positivebacteria diluted in a solution of 1:20 Tryptic soy broth supplementedwith 0.1% Triton X-100 (wetting agent). The petri dish incubated at 36°C. for 24 hours with humidity control. After the incubation period, thefabric samples were agitated in 10 mL neutralizing solution (Dey-Engleybroth), to remove the bacteria. The solutions of recovered bacteria werediluted and plated on agar plates, incubated for 24 hours at 37° C., andthen the CFUs were counted using standard methods. The final CFU countswere compared to those from similarly treated, time parallel negativecontrol fabric. The results against gram negative (Klebsiellapneumoniae) or gram positive (Staphylococcus aureus) or gram negativeEscherichia coli bacteria are presented in Table 4 below. For S. aureuseither ATCC strain 33592 or 6538 was used, while for K. pneumonia ATCCstrain 4352 was used.

Fabric was tested against the fungus T. mentagrophytes (ATCC 9533) asfollows. A one ml volume of dilute T. mentagrophytes spore preparationwas used to inoculate each control and test replicate, which were 5 cmdiameter circles of fabric. Inoculated carriers were sealed andincubated for 96 hours followed by elution of the fungus from the fabricvia agitation in 10 ml D/E broth with 10-20 sterile glass beads.Neutralized samples were vortexed for 20-30 seconds and the elutentpassed through sterile glass wool. Filtered samples were enumerated viastandard dilution and pour plate technique and incubated at roomtemperature for approximately 96 hours. The results reported below inTable 4 were calculated based on comparison to a 96 hour control(untreated) sample.

TABLE 4 Antimicrobial Activity of Fabrics Using AATCC 100 ProtocolExample Description K. pneumonia S. aureus E. coli T. menta 2 Knit PETFabric ++ +++ +++ 4 Knit PET Fabric +++ ++ +++ 6 Knit PET Fabric + + 7Woven PET Fabric +++ +++ 100% active yarn 8 Woven PET Fabric +++ +++ 75%active yarn 16 Woven PET Fabric 100% active yarn 17 Woven PET Fabric 75%active yarn 25% polyester 18 Woven PET Fabric +++ 75% active yarn 25%tencel 19 Woven PET Fabric +++ 50% active PET, 50% wool 20 Woven PETFabric + 50% active PET, 50% cotton 21 Knitted Fabric +++ +++ Yarn 10%active and 90% thermolite 22 Woven Fabric ++ ++ 10% active yarn 90%trevica yarn 23 Woven Fabric ++ ++ 20% active yarn 80% trevicayarn + >99%; ++ >/=99.9%; +++ >/=99.99%

Fabric from Example 6 was tested against two resistant strains each ofseven different antibiotic resistant bacteria. The resistant strains andthe activity of the fabric from Example 6 are reported in Table 5. Theactivities were determined using the same AATCC 100 based textileantibacterial protocol described above.

TABLE 5 Activity of Fabric from Example 6 Against Drug ResistantBacteria Drug Resistant % Inhibition @ Bacteria strains 30 min 2 h 24 hKPC producing Klebsiella pneumonia 20651.023 99.96 >99.99 >99.9920651.034 99.88 99.99 99.99 Methicillin Resistant Staph aureusC-11-43 >99.97 >99.98 >99.99 C-11-14 99.82 >99.99 >99.99 VancomycinResistant Enterococcus C-11-9 99.21 >99.91 >99.99 C-11-3157.14 >99.89 >99.99 MDR Pseudomonas aeruginosa03-H-23 >99.98 >99.98 >99.99 03-C-102 >99.99 >99.99 >99.99 MDRAcinetobacter C-11-42 >99.96 >99.98 >99.99 C-11-64 >99.97 >99.99 >99.993rd Generation Cephalosporin Resistant E. CloacaeCL-13-1 >99.99 >99.99 >99.99 CL-13-2 >99.99 >99.99 >99.99 FluconazoleResistant Candida albicans 20535.043 >99.99 >99.99 >99.9920323.083 >99.99 >99.99 >99.99

Alternatively, fiber was examined for its ability to inhibit E. coliusing an ATP (adenosine triphosphate) detecting technology. Smallsamples of fiber or fabric were incubated in 1.7-mL centrifuge tubes atroom temperature with (E. coli, ATCC 11229C) in Luria-Miller broth or0.9% saline, containing 0.02% Triton X-100. At various times, 0.4 ml ofBactitre Glo reagent (Promega Inc.) were added to stop the incubationand the level of ATP determined in a Luminometer (Promega Inc.) asmeasured in RLUs (relative light units). RLUs of time=zero controlcultures were compared to those obtained during the course of theexperiment to determine percent inhibitions. The data is presented inTable 6.

TABLE 6 Antimicrobial Activity of Fiber and Fabrics with E. coli in ATPAssay Time to 90% Example Description Inhibition  1 PET Fiber 20 min  2Knit PET Fabric 30 min  3 PET Fiber 10 min  4 Knit PET Fabric 15 min  5PET Fiber 15 min  6 Knit PET Fabric 50 min  7 Woven PET Fabric 10 min100% active yarn  8 Woven PET Fabric >50 min 75% active yarn  9 PETFiber 50 min 10 PET Fiber 30 min 11 PET Fiber >50 min 12 PET Fiber >50min 13 PET Fiber 50 min 14 PET Fiber >50 min 15 PET Fiber 30 min 16Woven PET Fabric 4 min 100% active yarn 17 lab coat Woven PET Fabric ND75% active yarn 25% polyester 18 scrub Woven PET Fabric 50 min 75%active yarn 25% tencel 19 112712A fiber Woven PET Fabric >50 min 50%active PET, 50% wool 20 112712A fiber Woven PET Fabric >50 min 50%active PET, 50% cotton 21 Knitted Fabric 30 min Yarn 10% active and 90%Thermolite 22 Woven Fabric Not done 10% active yarn 90% Trevica yarn 23Woven Fabric Not done 20% active yarn 80% Trevica yarn

TABLE 7 Expected and calculated silver salt contents. w/w % w/w %Measured silver salt silver salt Stage Fabric # Ag (calculated)(expected) Development 091812F1 2,430 ppm 0.35% 0.35% Run (Example 1)Development 092812K 2,270 ppm 0.33% 0.35% Run (Example 4) Production112712K 2,260 ppm 0.33% 0.35% Run (Example 6)

Table 7 shows the expected and calculated silver salt content of fibersdiscussed in the specified Examples. Silver content was measured byICP-OES elemental analysis. The table shows that the silver salt contentof the fibers was very close to expected levels.

The activity of antimicrobial fabrics against a variety of microbes wasdetermined by testing fabrics according to the AATCC 100 protocol. Inbrief, the tested fabrics were inoculated with about 1×10⁵ CFU/mL ofmicrobe and then incubated under growth conditions. Bacteria were thenharvested from the test articles at specified times in neutralizingbroth and plated on agar. The agar plates were then incubated and theCFU's counted. The results are shown in Tables 8 and 9.

TABLE 8 Antimicrobial activity of Fabric 092812K Bacteria killedBacterial killed 2 hr incubation 24 hr incubation Bacteria time time E.faecalis >99.9% >99.9% S. aureus >99.9% >99.9% K. pneumoniae 99.999%99.999% A. baumannii 97.3% >99.9% P. aeruginosa >99.9% 99.999% E.cloacae >99.9% >99.99% P. vulgaris >99.9% 99.999% C. albicans >99.9%99.999% E. coli >99.9% >99.9%

TABLE 9 Antimicrobial activity of Fabric 112712K Bacteria killedBacteria killed E. faecalis >99.9% 99.999% S. aureus >99.9% 99.99% K.pneumoniae >99.9% 99.999% A. baumannii >99.99% >99.9% P.aeruginosa >99.9% 99.999% E. cloacae >99.9% >99.9% P. vulgaris >99.9%99.999% C. albicans 99.54% >99.9% E. coli >99.9% >99.9%

Tables 8 and 9 show that the tested fabrics have significantantimicrobial activity against a range of bacteria including S. aureus.

Tables 10 and 11 demonstrate the effect of washing on the silver contentand antimicrobial activity of fabrics was tested. The fabrics werewashed fifty times according to the AATCC 61 washing protocol. Thesilver levels and the antimicrobial activity were determined by ICP-OESand the AATCC 100 protocol, respectively, after specified numbers ofwashings. Titanium dioxide (a white dye) levels were also tested as acontrol measurement. The results show that the silver content decreasedby less than 5% after 50 washings. Further, there was no significantdecrease in antimicrobial activity after 50 washings.

TABLE 10 Silver Levels Over 50 Washes White 100% PT White 100% PT Numberof Fabric Measured Fabric Measured Washings Silver Titanium 0 2310 ppm1680 ppm 5 2230 ppm 10 2220 ppm 20 2190 ppm 25 2190 ppm 1660 ppm 30 2320ppm 40 2190 ppm 50 2190 ppm 1700 ppm

TABLE 11 Antimicrobial Activity Against S. aureus (ATCC 6538) Over 50Washings White 100% PT Blue 75% PT Fabric % Fabric % Number ofInhibition of Inhibition of Washings MRSA @ 24 h MRSA @ 24 h 0 99.99%99.99% 5 99.99% 99.99% 10 99.99% 99.99% 20 99.99% 99.99% 25 99.99%99.99% 30 99.99% 99.8% 40 99.99% 99.97% 50 99.99% 99.8%

The activity of antimicrobial fabric 091812F1-UW against Trichophytonmentagrophytes (T. mentagrophytes), a fungus commonly found in athlete'sfoot patients. Table 12 shows that the fabric has significant activityagainst T. mentagrophytes. Specifically, the CFU counts decrease by over99% after 96 hours.

TABLE 12 Antimicrobial activity against T. mentagrophytes % Reduction %Reduction Compared to Test Average Compared to Control at MicroorganismSubstance Time Point CFU/Swatch CFU/Swatch Time Zero 96 Hours T.mentagrophytes 100% Polyester Time Zero 1.25E+04 1.43E+04 N/A ATCC 9533Black Control 1.60E+04 96 Hours 3.50E+06 3.50E+06 Inconclusive⁺091812F1-UW 96 Hours <50 <50 99.6491% 99.9986% <50

The results in Table 12 are displayed as a bar graph in FIG. 11.

FIG. 12 compares images of a control fabric (left) without antimicrobialsilver particles and fabric 091812F1-UW (right) after exposure to T.mentagrophytes. Fungus is visible in the control fabric but not on the091812F1-UW fabric.

Thus, the antimicrobial fabrics have demonstrated anti-bacterial andanti-fungal activity.

The invention claimed is:
 1. A polymer composition comprising: (a) afirst population of high-melting polymer particles; (b) about 1 to about26 wt.% of a silver salt having the formula Ag_(a)X_(b)Y_(c)Z_(d); (c)about 0.1 to about 2.6 wt.% of a copper salt having the formulaCu_(a)X_(b)Y_(c)Z_(d); and (d) about 0.15 to about 3 wt.% of acompounding agent; Ag is Ag(I) or Ag(II), and a is 1 to 4; each X issulfur, and b is independently 1 to 4; each Y is oxygen, and c isindependently 2 to 8; each Z is independently H; C₁-C₁₄ alkyl; C₃-C₈cycloalkyl; C₁-C₈ alkyl substituted by C₃-C₆ cycloalkyl; C₁-C₈ alkyloptionally substituted by C₆-C₁₀ aryl; C₆-C₁₀ aryl; C₆-C ₁₀ arylsubstituted by C₁-C₁₄ alkyl, C₃-C₈ cycloalkyl, C₁-C₈ alkyl substitutedby C₃-C₆ cycloalkyl, or halogen; d is 0 or 1; wherein a mixture of thesilver salt, copper salt, and compounding agent is disposed over thesurface of the high-melting polymer particles.
 2. The polymercomposition of claim 1, wherein the high-melting polymer particlescomprise a polyethylene terephthalate polymer, Nylon 6, or Nylon 6,6. 3.The polymer composition of claim 1, wherein the compounding agent is oneor more compounds selected from the group consisting ofpolydimethylsiloxane, hydroxyl terminated polydimethylsiloxane,amorphous silica, aliphatic hydrocarbons, aliphatic petroleumdistillates, and liquefied petroleum gas.
 4. The polymer composition ofclaim 2, wherein the compounding agent comprises a mixture ofpolydimethylsiloxane, hydroxyl terminated dimethylsiloxane, andamorphous silica.
 5. The polymer composition of claim 1, furthercomprising a pigment and an optical brightener.
 6. The polymercomposition of claim 5, wherein the pigment is titanium dioxide.
 7. Thepolymer composition of claim 1, wherein the polymer composition has notbeen subjected to heating in excess of about 110° C.
 8. A polymermixture comprising the combination of the polymer composition of claim 1with a second population of high-melting polymer particles, whereby thepolymer mixture has the following composition: (i) about 0.05 to about0.50 wt. % silver salt having the formula Ag_(a)X_(b)Y_(c)Z_(d); (ii)about 0.01 to about 0.1 wt. % copper salt having the formulaCu_(a)X_(b)Y_(c)Z_(d); (iii) about 0.01 to about 0.1 wt. % compoundingagent ; and (iv) high-melting polymer particles from the first andsecond populations of high-melting polymer particles.
 9. The polymermixture of claim 8, wherein the high-melting polymer particles from thefirst and second populations of high-melting polymer particles comprisea polyethylene terephthalate polymer.
 10. The polymer mixture of claim8, further comprising about 0.0002 to about
 0. 025% NaIO₄.
 11. Thepolymer mixture of claim 8, further comprising a pigment and an opticalbrightener.
 12. The polymer mixture of claim 11, wherein the pigment istitanium dioxide.
 13. The polymer mixture of claim 8, in the form of amelt spun fiber.
 14. The polymer mixture of claim 9, in the form of amelt spun fiber.
 15. A method of making the polymer composition of claim1 comprising coating a mixture of the compounding agent, silver salt,and copper salt over the surface of the high-melting polymer particles.16. The method of claim 15, wherein the high-melting polymer particlescomprise a polyethylene terephthalate polymer.
 17. The method of claim15, wherein said coating comprises: (1) coating the first population ofhigh-melting polymer particles with the compounding agent; and (2)adding the silver salt and copper salt to the coated high-meltingpolymer particles, thereby forming a mixture of the silver salt, coppersalt, and compounding agent disposed over the surface of thehigh-melting polymer particles.
 18. The method of claim 17, wherein thehigh-melting polymer particles comprise a polyethylene terephthalatepolymer, nylon 6, or nylon 6,6.
 19. A method of making the polymermixture of claim 8, comprising mixing the first population ofhigh-melting polymer particles, having a mixture of compounding agent,silver salt having the formula Ag_(a)X_(b)Y_(c)Z_(d), and copper salthaving the formula Cu_(z)X_(b)Y_(c)Z_(d)disposed over the surfacethereof, with the second population of high-melting polymer particles.